Abstract
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 149:91-104 (1997) - doi:10.3354/meps149091 Growth and egg production of female Calanus finmarchicus: an individual-based physiological model and experimental validation Carlotti F, Hirche HJ A detailed individual-based model of egg production of Calanus finmarchicus is proposed. Female growth and egg production are represented by 8 state variables (gut content, nutrient pool, structural body, oil sac, and 4 stages of oocyte maturation) which are regulated by physiological processes. Clutch size is set constant under continuous food conditions, but the spawning interval changes with food availability and temperature depending on the rate of oocyte maturation. Smaller clutches can occur when eggs are released under bad external conditions. Thus changing conditions can produce different clutch size distributions. For model validation, egg production experiments were conducted under different constant and fluctuating food concentrations and compared with model simulations. In the experiments, egg production was strongly affected by food fluctuation. In experiments with alternating feeding and starvation cycles integrated egg production was affected by mean food concentration during the experiment rather than by the frequency of the cycles. The model reproduces correctly the egg production rates and final body carbon of females kept in the different food regimes. It provides a dynamical explanation of physiological responses of the individual under short-term food variation. When food becomes unavailable, the most advanced oocytes are released and egg production continues until the nutrient pool decreases below a minimal critical value. Thereafter, no eggs are laid. When food reappears, somatic growth resumes until structural body weight is restored, then oogenesis is fuelled. Experimental results were simulated correctly without using matter from the lipid pool. Calanus finmarchicus · Egg production · Physiological model · Growth Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 149. Publication date: April 10, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.
Highlights
The copepod Calanus finmarchicus is a key species in the pelagic system of the northern North Atlantic, where it is a n important link between phytoplankton and fish populations that feed on Calanus spp. eggs and juveniles during the early larval stages (Runge 1988, Ohnian & Runge 1994) Due to C. finmal-chicus reproductive strategy, its breeding is much more episodic than that of smaller copepod species, for whom it is more continuous (Frost 1985, Marshal1 1949).This high variability in recruitment has a strong bearing on higher trophic levels in Calanus-dominated systems, and on the phytoplankton through the changing grazing pressure (Carlotti & Radach 1996)
We concluded that the initial food concentration of 25 000 cells ml-' limlted egg production
Sciandra et al (1990) presented the first model of reproduction of calanoid copepods which represented a non-linearity between fluctuations of food andegg production
Summary
The copepod Calanus finmarchicus is a key species in the pelagic system of the northern North Atlantic, where it is a n important link between phytoplankton and fish populations that feed on Calanus spp. eggs and juveniles during the early larval stages (Runge 1988, Ohnian & Runge 1994) Due to C. finmal-chicus reproductive strategy, its breeding is much more episodic than that of smaller copepod species, for whom it is more continuous (Frost 1985, Marshal1 1949).This high variability in recruitment has a strong bearing on higher trophic levels in Calanus-dominated systems, and on the phytoplankton through the changing grazing pressure (Carlotti & Radach 1996). The reproductive biology of Calanus finmarchicus has been studied extensively in the laboratory under different food and temperature conditions (Runge 1985, Hirche et al 1997) a n d In the field in different regions (e.g. Marsh.al1 & Orr 1955, Runge 1985, Hirche 1990, Die1 & Tande 1992, Ohman & Runge 1994) and has recently been reviewed by Hirche (1996). These studies have not integrated female reproductive physiology with growth and general metabolism. Niehoff production in constant and varying food conditions. & Hirche (1996)have recently studied in detail the oo-
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